Support more granular ACLs

Previously, dumbno could only add an acl for one of two requests:

• a full 5 tuple like (proto, src, src port, dst, dst port)
• a 2 tuple like (src, dst)

Now, it supports tuples of things like

• (proto, src, dst, dstport)
• (proto, src, srcport)

Which can be useful if a particular service on a host is particular chatty across a large number of connections. This could be useful for shunting responses from an external CDN host by adding

proto=tcp, src=some.cdn.host, sport=443